A schistosomiasis model with different infection degrees is established considering the fact that a mild infected person may convert into a severe infected person under some conditions.The equilibrium point and threshold of disease outbreak are calculated.According to the sign of the characteristic root and the principle of LaSalle invariance,the disease-free equilibrium is not only locally asymptotically stable but also globally asymptotically stable.According to the Hurwitz discriminant theorem,the endemic equilibrium is locally asymptotically stable,which is proved by simulation.The impact of different infection degrees on the number of patients and the basic reproduction number is discussed.It is found that the transformation from a mild infected person to a severe infected person produces more complex effects.